Does your motherboard have any diagnostic leds? What do they indicate? (Most diagnostic leds indicate a serviceable state so the next unlit led is the point of failure)

For future reference, what were the last settings you input to bios?

Power down the system and ensure all connections (including power, cabling, fan headers) are firmly seated. Nothing worse than spending hours trying to bring your board back to life only to discover that the issues are unrelated to your bios tweaks.

This would also be a good time to unplug any external devices from your system on the chance that they (or your USB connections) are the cause of the problem.

If the board will allow you to get into bios, but won't boot into OS, load default (or safe on some boards) settings first and then try optimized settings.

Check your hardware settings while you're in there to ensure that the system still recognizes your HDs, and that the boot order is correct. (If your HD isn't recognized, slave in a different one to see if it's a hardware failure)

This is not the time to attempt a bios flash!!! A bios flash should be one of the last options you try as you don't yet know if your system is stable enough to accept it.

Still no joy? Time for a C-MOS reset.

Many new boards have 2 sets of jumpers for c-mos reset. Try the “reset to last known good settings” option first and then try a full reset.

I like to leave the reset jumpers in place for at least a minute (we'll get to a “long reset” in another step)

If the reset works, go into bios and set for default/optimum. Make any system specific changes such as boot order etc......

If you've gotten this far without any luck, you more than likely have a resource conflict within bios that's preventing it from properly resetting. It's time to roll up your sleeves and get to the dirty work of finding the conflict. The main goal here is to find a configuration that will allow your system to post normally in order to reset your bios settings or flash bios if necessary.

Break your system down to a basic build. (Best is actually outside of case to ensure that there are no shorts between the motherboard & the case)

PS2 keyboard & mouse if you can get your hands on them (takes USB right out of the picture)

Unplug all non-essential connections from your motherboard. Don't forget the (Non-CPU) fans plugged into the motherboard headers, as well as USB/Audio/Firewire headers.

If possible, use another system as a test bed for the parts you are going to use in your basic build, or better yet, use parts from another system which are known to be serviceable.

Start testing individual components/slots, doing a full c-mos reset after each switch.

Test single memory stick in each slot, try different sticks if you don't have a test bed to confirm serviceability of memory.

Try running the CPU fan off of a different motherboard header. (Scoff if you will... this worked on my last “no post”)

Swap video card into secondary slot or use a PCI video card if available.

Swap IDE/SATA ports (use different/serviceable cables)

If any one of the above allows you into bios, set bios for “default” or “optimum” settings and then start replacing components one at a time (in the opposite order) to ensure that the bios reset has returned your system to normal.

If you manage to get a working configuration out of step 6, but the bios will not reset to normal (system fails after replacing components), it's time to attempt a bios flash.

Warning!!! Aside from pouring molten lead on your motherboard, flashing the bios on a system before first ensuring stability is without a doubt the single most popular method of permanently damaging it

Return system to working configuration

Verify system stability by running a mem386 boot CD (minimum 2 full passes)

Flash bios using safest available method (Bootable CD or floppy with Ramdisk is my choice)

Still here? We're getting pretty close to that 5% of unrecoverable “no post” faults, but there's a chance that a “long” c-mos reset might be the ticket to send you back to your happy place.

Disconnect the PSU power plug, and press the “on” switch to drain the capacitors on your PSU & motherboard.

Remove the battery from the motherboard.

Set the c-mos jumper for full reset & leave it set for 24 hours.

If after all of this you're still looking at a blank screen, the only option left is to either buy a pre-flashed replacement bios chip, or if you're lucky, find somebody local who can flash your chip for you. (There's also the good old “hot flash” if you've got access to a working model of the same revision motherboard, but I'll let you Google that yourself rather than risk being blamed for any resulting fireworks....).

Well, that's it. 20+ years of computing & almost 10 years of building my own and that's the best I can come up with...

I have personally needed to use every one of these 10 steps but never had any luck with #9, nor bothered to order a replacement bios after failing to find someone local who could flash one for me.

I decided it was time to cut my losses and pick up another motherboard rather than spend money on something that I'd not only have to wait for, but also might not repair the board.

That said.... prices on good S775 boards are currently so high that it would be worth it to pay $25 or so in a final attempt to resuscitate them. (Maybe more local shops will invest in bios burners).